Tuesday, 11 December 2012

A layperson's guide to your DNA and why mapping it is important for future cancer and other treatments and prevention.

The sun rose today and the government announced that it was going to fund something big. £100 million will be spent mapping the DNA sequences of 100,000 sufferers of cancers and other rare diseases in the UK. This will be the start of a genetic revolution in medicine! How?

After your parents had enjoyed that creative night of passion, a solitary sperm and a giant egg (relative to the sperm) fused together. Now they shared the 3 billion plus bits of information. That information is encoded in your DNA.

Three billion bits of information fits comfortably onto a shiny film DVD. And as the digital information on the DVD recreates a wonderful film, the information in the DNA provides the instructions to create the incredible unique individual that is you.

We know, (OK, engineers and scientists know), how to make the film DVD with its microscopic digital instructions and read these on a DVD player. We are only beginning to understand the very basics of small parts of the DNA that makes up our human genome. We can recognise bits of DNA as genes with particular functions like making haemoglobin or digesting your food. But, to be honest, we are still a very long way off understanding how all the instructions are transformed into the miraculous you and me.

So, the strategy behind mapping the DNAs of 100,000 sufferers of cancer and other diseases is: To see if there are any differences or common features in the information encoded in the 100,000 DNAs by comparing them. Comparing 3 billion bits of information from each individual within even a select group is going to be an enormous task. After all, three billion letters is about 1500 volumes of the fat Harry Pottter book (Harry Potter and the Order of the Phoenix).

Fortunately, mapping your DNA has become a lot cheaper. Let's ignore the billions of years of natural evolution leading to humanity. Perhaps we should also draw a discrete veil over the financial investment in romance leading to the nights of passion that created you and me. Mapping your DNA sequence currently costs between £5,000 and £10,000. This is about 1% of the cost of mapping the first human genome in 2011, estimated at £500m!

£100m is therefore quite reasonable for the 100, 000 shiny DVDs worth of DNA information. After all, a good studio production to create an equivalent film costs tens of millions of pounds, so the investment sum is equivalent financing this year's blockbusters. And if you use double sided BlueRay discs, you can store the information more conveniently on only 7500 disks!

It is going to take years just to do the mapping of the 100,000 human DNA sequences. It will take even longer for all the discoveries and research to lead to successful treatments. So this is for the long term.

However, there will a point in the future where an older you or our children can go to the doctor, have our DNA sequences mapped at relatively low cost - and receive preventative treatment tailored to our unique individual genetic heritage.